1. Field of the Invention
This invention relates to a gate assembly for a hopper of a transport vehicle and, more particularly, to a gate assembly having a gate that moves longitudinally along guides from a first plane in a closed position to a second plane in an open position.
2. Description of the Prior Art
Gate assemblies for transport trailers and other vehicles are known. Previous gate assemblies do not provide a sufficiently large opening, or they are difficult to operate, or they occupy too much space, or the opening is much smaller than the footprint when the assembly is in the open position, or the particulate material passing through the gate assembly is subject to contamination due to the design of the assembly.
In FIG. 1, there are shown two prior art manual drop gates 2 operated by a crank 4. When the crank is turned in an appropriate direction, the gates open and particulate material from a hopper 6 falls by gravity into a channel 8 containing an auger (not shown) or other means for transporting the particulate material. The opening provided by the drop gates is too narrow and restrictive for efficient flow of materials where the materials are not free flowing. The drop gates 2 block part of the opening.
In FIG. 2, there is shown a prior art transverse gate 12 that is flat and is moved between a closed position (as shown) and an open position by means of a rack 14 and pinion 16. The gate can be moved entirely to one side of the transport vehicle in the open position or, alternatively, the gate can be split in half with a rack and pinion on each side of the hopper to move each half of the gate outward when the gate is being opened and inward when the gate is being closed. While the gate provides a larger opening than the drop gates shown in FIG. 1, the transverse gate 12 opens into an exterior of the hopper. This can lead to spillage of material if the area between the open gate and the hopper is not adequately sealed or if the seals become worn and also exposes the gates to the ambient air. This can risk contamination of the bulk material (not shown) within the hopper. Also, depending on the weather conditions, the gate can become stuck in a particular position.
In FIG. 3, there is shown a prior art longitudinal gate assembly 20 where there are three gates 22, 24, 26 located adjacent to one another in the gate assembly 20. When, for example, gate 22 is opened, it will slide on top of or beneath gate 24. Similarly, when gate 24 is opened, it will slide on top or beneath gate 26. When gate 26 is opened, it will slide on top or beneath an adjacent plate 28. Each of the gates 22, 24, 26 has a separate compartment or hopper (not shown), which can be filled with bulk material. Usually the gate that is being opened slides beneath an adjacent gate. The difficulty arises when the hopper for gate 26, for example, is filled with bulk material and the gate is flexed downward due to the weight of that material. As a result, the gate 24 can therefore be difficult to open or close and sometimes cannot be opened or closed as it cannot slide beneath the gate 26. Each of the gates 22, 24, 26 has a crank 30 thereon. The gate assembly 20 does not permit the use of different gate sizes. Also, when gate 22 is in the open position, since gate 22 slides beneath gate 24, if it were desired to open gates 24 simultaneously with gate 22, gate 22 will be blocking most of the opening of gate 24.
In FIGS. 4 and 5, there are shown prior art vertically inclined slide gates 32, 34 respectively. Gate 32 is opened by an air operated cylinder 36 and gate 34 is opened and closed by a rack and pinion 38 with a crank 40. As can be seen from the drawings, in an open position, the gates are pulled upward into an inverted V position providing an opening through which materials can flow into the discharge area 8. These gates function well when the materials are free flowing, but the openings are not large enough to permit the flow of bulky non-free flowing products. Since these gates operate within the interior of the hopper, risk of contamination of materials is reduced.